Periodontal disease is an umbrella term for a variety of dental conditions associated with either gingivitis or periodontitis. Gingivitis is an inflammation of the gingiva, commonly known as gums, that is commonly associated with poor oral hygiene and/or the hormonal state of the patient. If left untreated, gingivitis may develop into periodontitis.
Periodontitis is a bacterial disease in which the infection has progressed to involve the oral tissues that retain the teeth in the jawbone. With this disease the gums become red and inflamed. This condition, if untreated, results in damage to the ligaments and bone holding the teeth in place, and formation of pockets around the teeth. As the pockets become deeper, teeth loosen, to a point where they may fall out. The severity of periodontitis is determined by dentists and other dental practitioners, by measuring the depth of these pockets and reviewing x-rays of the teeth and jawbone.
Periodontal disease involves a different treatment protocol than other oral diseases. While many oral diseases can be treated with proper hygiene, fluoride, pastes, washes and rinses, periodontal disease is often more retractile to treatment. This is because of differences between the oral and periodontal cavities. The oral cavity is essentially an aerobic environment, constantly perfused by saliva. In contrast, the periodontal cavity is more anaerobic, and is perfused by plasma filtrate, known as “crevicular fluid.” The growth of microorganisms within the periodontal cavity microenvironment may cause periodontal disease. As the disease progresses, the periodontal microenvironment becomes more anaerobic, and the flow of crevicular fluid increases.
Efforts to treat periodontal disease have met with limited degrees of success. This is because the site of the bacterial infections in the periodontal cavity are largely inaccessible to agents present in the oral cavity as well as agents provided to the oral cavity, such as mouthwashes, rinses and the like. Moreover, the increased outflow of crevicular fluid that accompanies periodontal disease inhibits therapeutic agents placed into the oral cavity from entering the pockets.
Oral systemic administration of antibiotics has been shown to be a useful method of controlling subgingival flora. However, because of side effects, such as those of the digestive system, oral systemic administration has had only limited use in treating periodontal disease. Oral systemic therapy also requires frequent dosing, so patient compliance is frequently a problem.
Recently, efforts have focused on delivering therapeutic agents directly to these pockets, in some cases, in a controlled release formulation. In general, administration of agents directly to the pocket permits higher local drug concentrations that can be achieved by systemic administration. Also, some agents such as tissue growth factors must be administered directly to the target site, i.e., the periodontal pocket. Also, as these products are typically administered by dental professionals patient compliance is not of moment here.
U.S. Pat. No. 4,175,326 to Goodson discloses the use of a drug-filled polymer hollow fiber. The disclosed delivery system is tied around a tooth and gently pressed below the margin of the gingiva so that it resides in the periodontal pocket, and can deliver tetracycline for a prolonged period, such as a week or more.
Although these devices may be able to dispense an appropriate drug for a time span of a week or more, they have not been widely used. This is because their application is difficult and time consuming and the device may be dislodged by the patient during tooth brushing, flossing or eating.
The aforementioned disadvantages were overcome by administration of microparticles in dry form to the periodontal pocket by use of an apparatus disclosed in U.S. Pat. Nos. 5,236,355, 5,366,733 and 5,622,498, all to Brizzolara, et al., all three patents are incorporated by reference herein. These patents disclose treating dental diseases by administration of dry microparticles to the periodontal pocket. Microparticles suitable for this purpose may have compositions, as described in U.S. Pat. Nos. 5,000,886, 5,143,661 and 5,500,228, all to Lawter, et al., all three of these patents incorporated by reference herein, and U.S. Pat. Nos. 5,236,355, 5,366,733 and 5,622,498, all to Brizzolara, et al., and may be produced by the methods disclosed in the aforementioned six U.S. patents.